Probemat fixtures, also referred to as a bed-of-nails fixtures, are used in automatic circuit pack testing systems to make electrical contact over the whole surface of a circuit pack. An example of an automatic circuit pack testing system is the GenRad 2276. The average fixture has from 500 to 2000 test probes. As the fixture is used, the ends of the probes become contaminated with material from the circuit packs and cease to make good electric connections. Cleaning with solvents is not possible because each probe is a spring-loaded pin plunger and barrel using a special lubricant. If a solvent was used to clean the test probes, the solvent would remove the lubricant. In addition, the solvent would tend to deposit particles between the barrel and the pin plunger.
In the prior art, probemat fixture maintenance has relied on simply light brushing, vacuuming, and random test probe replacement. Because of the high cost of replacing many test probes, probemat fixture maintenance intervals have often been too long and have resulted in poor testing being performed by the automatic circuit pack test systems. Abrasive cleaning, using sand or other hard materials, is not used because such materials remove the gold or other platings on the test probe surfaces. Abrasive materials also fracture to create dust that greatly shortens the life of the test probes. Further, the probemat fixtures have active electronic circuits permanently mounted on the probemat fixtures, and these active electronic circuits are very susceptible to damage by electrostatic charges being built up on the probemat fixture during cleaning.
The problem of having probemat fixtures whose test probes are not clean of contaminants is a major problem in the area of automatic circuit pack testing systems. Clearly, the cleaning of the test probes is a long outstanding problem within the industry which the prior art has not been able to solve.